The present invention relates to pianos, organs, harpsichords and the like which include a keyboard by which the instrument is played. In particular, the invention is concerned with the key bed which underlies the keyboard and supports the keys within the structural frame of the instrument.
The key bed in pianos and the like plays several important roles in the instrument frame. It is a structural member which extends between the arms of the frame at the front of the piano and also provides a level platform on which the keys, their hinges and stops and associated portions of the piano action are supported. In the past it has been customary to construct the key bed of laminated hardwoods which are sealed to resist moisture and protect against warpage. Since the bed supports the keys, any warpage of the bed displaces the keys and can interfere with the regulation that establishes identical function and timing of the keys, their associated actions and the strings. The warpage may totally prevent operation of the individual keys but even slight malfunctions may cause the response to depression of the keys to be so significantly degraded that satisfactory performance is impossible. Increased pressures, sticking keys, lost motion, or slow return of the keys and lifting of the dampers significantly interferes with the touch or feel of the piano or affects the sound produced by the strings.
In spite of the precautions taken to prevent warpage of the key bed, problems can arise which require repair or replacement of the key bed. Such repairs are costly and time consuming due to the extensive disassembly and reassembly process required to reach and work on the key bed in the underlying structure of the piano.
It is accordingly a general object of the present invention to provide an improved key bed for the keyboard of a piano or the like and which is economical to produce and has a high stiffness to resist warpage and distortion.